The present invention relates to a post-processing device and an image forming apparatus provided with the post-processing device.
As a conventional sheet post-processing device, a sheet post-processing device shown in FIG. 11, which is disclosed in Japanese Patent Publication (KOKAI) No. H1-313261, is known. A sheet post-processing device 100 in FIG. 11 is disposed outside an image forming apparatus main body 101, and a placement tray 102 is disposed outside the sheet post-processing device 100.
In FIG. 11, a sheet S copied in the image forming apparatus main body 101 and fed out by a paper ejection roller 105 is transferred to the sheet post-processing device 100 attached to an outside of the image forming apparatus main body 101. The sheets S transferred to the sheet post-processing device 100 are stapled by a staple unit 103 provided in the sheet post-processing device 100.
The sheets S in which stapling is finished are pushed by an abutting member 104 to be placed on the placement tray 102. The abutting member 104 supports rear ends of the sheets S in a transferring direction to thereby align the rear ends, and when the stapling is finished, the abutting member 104 pushes the rear ends of the sheets S toward the placement tray 102.
The sheet post-processing device 100 is attached to an outside of a side surface of the image forming apparatus main device 101 shown in FIG. 11, and the placement tray 102 is attached to an outside of the sheet post-processing device 100. Therefore, when the sheet post-processing device 100 is installed in the image forming apparatus main body 101, an installation area for the image forming apparatus main body 101 becomes large.
In order to solve the aforementioned problem, there is an image forming apparatus 106 shown in FIG. 12, which is disclosed in Japanese Patent Publication (KOKAI) No. 2000-86076. In this structure, a sheet post-processing device 107 is installed between an image forming apparatus 106 and an image reading device 108. In the image forming apparatus 106 structured as described above, an installation area for the image forming apparatus 106 is reduced by a portion of the sheet post-processing device 107 assembled inside the image forming apparatus main body 106.
However, a placement tray 109 on which the post-processed sheets S are placed remains to be projected outside from a side surface of the image forming apparatus 106. Usually, a size of the placement tray 109 is extremely larger than that of the sheet post-processing device 107, so that if the placement tray 109 remains to be projected, the installation area is not reduced.
Thus, as in a structure shown in FIG. 13 which is disclosed in Japanese Patent Publication (KOKAI) No. H8-277059, there has been known a structure in which a sheet post-processing device 110 is attached above a placement tray 111. The sheet post-processing device 110 includes an internal tray 112. The internal tray 112 is formed of two trays, that is, a first tray 112a and a second tray 112b. The internal tray 112 structured as described above opens like a door from a connecting portion between the two trays toward the placement tray 111.
The sheets S are stapled on the internal tray 112, and when the stapling is finished, the internal tray 112 comes to an open condition. When the internal tray 112 is in the open condition, a set of the sheets S falls onto the placement tray 111 by its own weight to be placed on the placement tray 111.
Therefore, since the internal tray 112 for supporting an entire surface of the sheet to which the stapling is applied and the placement tray for placing the stapled sheets are disposed vertically in parallel, the installation area for the post-processing device 110 can be reduced.
However, since the internal tray 112 is opened and closed like a door, the sheet post-processing device 110 is required to have a height sufficient for allowing the internal tray 112 to open. Thus, it is extremely difficult to assemble the sheet post-processing device 110 inside the image forming apparatus. Supposing that the sheet post-processing device 110 is assembled inside the image forming apparatus, when the sheet post-processing device 110 which is considerably high in order to open the internal tray is assembled inside the image forming apparatus, the height of the image forming apparatus is increased.
When the height of the image forming apparatus is increased, in case a document subjected to the image forming is set on the image forming apparatus, a position of setting the document becomes high. If the position of setting the document is high, it becomes difficult to confirm the position of setting. Therefore, there is a problem that this tall image forming apparatus is difficult to use.
Moreover, in order to install the tall sheet post-processing device 110 described above inside the image forming apparatus, a large space is required inside the image forming apparatus. However, in the known image forming apparatuses, since it has been tried to minimize a size thereof as small as possible, the large space described above is normally not formed in the known image forming apparatuses. Therefore, in the known image forming apparatus, especially, there has been a problem that the sheet post-processing device 110 can not be installed inside the image forming apparatus.
Also, as shown in FIG. 14, there has been known a structure disclosed in Japanese Patent Publication (KOKAI) No. 8-143211, in which an auxiliary guide 150 for supporting only a rear end portion of a sheet is disposed above a displacement tray 140 at the highest portion of a plurality of trays to be freely capable of projecting and retracting, such that the sheet is supported by the auxiliary guide 150 and a stapler 155 is moved forward and backward with respect to the sheet in a direction orthogonal to a sheet transferring direction to carry out the stapling process.
However, in this device, it is necessary to move the stapler 155, which is relatively large and heavy, with respect to the sheet, and a motor for moving the stapler 155 also becomes bigger, so that the sheet post-processing device can not be made small. In addition, since the apparatus includes a plurality of trays, as in the aforementioned apparatus of FIG. 11, the sheet post-processing device is attached to the outside of the side surface of the image forming apparatus main body, so that an installation area for the image forming apparatus main body becomes large.
Accordingly, a first object of the invention is to provide an extremely compact sheet post-processing device.
A second object of the invention is to provide an image forming apparatus, in which an installation area for an entire image forming apparatus is not increased even if the sheet post-processing device is attached by selecting the installation site for the compact sheet post-processing device.
Further, a third object of the invention is to provide an image forming apparatus assembled with the sheet post-processing device, which can be easily assembled inside the known image forming apparatus and can be used easily without increasing an installation area of the image forming apparatus.
Further objects and advantages of the invention will be apparent from the following description of the invention.
To achieve the aforementioned objects, the present invention provides a sheet post-processing device for carrying out post-processing, such as a binding process or punching process, with respect to sheets ejected from an image forming apparatus main body. The sheet post-processing device comprises: a placing tray for placing sheets thereon; supporting means capable of moving between a support position for supporting upstream sides, in the transferring direction, of the sheets ejected above the placing tray, and a retreat position for allowing the supported sheets to drop onto the placing tray; post-processing means fixedly disposed at one end side of the supporting means and applying post-processing to the sheets supported on the supporting means; sheet shift means for shifting the sheets to a position where the sheets are released from the post-processing means; and control means for controlling the sheet shift means to shift the sheets from the post-processing means after the post-processing by the post-processing means is carried out. Also, the control means moves the supporting means to the retreat position.
Accordingly, since the placing tray and the supporting means are overlapped vertically, the space for the supporting means in the sheet transferring direction can be omitted, and there is no need to move the post-processing means, such as a stapler device, resulting in providing an extremely compact sheet post-processing device.
Also, the placing tray includes a first placing section, which supports forward ends of the sheets in the transferring direction, and a second placing section located below the supporting means. The second placing section is lower than the first placing section. Accordingly, the sheets can be extended over the supporting means and the placing tray to be processed, so that the post-processing can be surely carried out.
Also, the present invention provides an image forming apparatus, which comprises a placing tray formed on an upper surface of an image forming apparatus main body and placing sheets ejected from the image forming apparatus thereon; an ejecting section projected above the placing tray and disposed to be spaced away from the placing tray, in which the sheet ejecting section includes a sheet ejection port; and a sheet post-processing device including a unit formed of supporting means and post-processing means. The supporting means is provided between the placing tray and the sheet ejection port, and is capable of moving between a support position for supporting upstream sides, in the transferring direction, of the ejected sheets, and a retreat position for allowing the supported sheets to drop onto the placing tray. The post-processing means is disposed to be adjacent to one end side of the supporting means, and provided for applying post-processing to the sheets supported on the supporting means.
Further, the image forming apparatus described above further includes an image reading device for reading an image, which is disposed above the placing tray on the upper surface of the image forming apparatus main body and the ejecting section. The sheet post-processing device formed of the unit is disposed between the image reading device and the placing tray and located adjacent to the sheet ejection port.
Accordingly, there is no need to increase an installation area for the entire image forming apparatus. Even in case of the known image forming apparatus, the sheet post-processing device can be easily assembled therewith, and the image forming apparatus assembled with the sheet post-processing device, which is easy to use, can be provided without increasing the installation area for the image forming apparatus.